/* ----------- reglas generales y módulos ----------- */

* {
    box-sizing: border-box;
}

body {
    background-color: rgba(0, 255, 78, 0.1);
    margin: 0;
    font-family: "trebuchet ms", sans-serif;
    
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    min-height: 100vh;
}

header,
footer {
    background-color: rgba(0, 255, 69, 0.35);
}

img {
    max-width: 100%;
    height: auto;
}

.contenedor,
main > section {
    max-width: 40rem;
    margin: 0 auto;
    padding: 1rem;
}



/* ----------- header ----------- */

header > div > img {
    width: 6rem;
    background-color: white;
    padding: .5em
}

header > div {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
}

nav ul {
    list-style: none;
    margin: 0;
    padding: .5em;
    
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
}

nav ul li a {
    background-color: rgba(0, 0, 0, 0.5);
    border: solid 2px rgba(255, 255, 255, 0.9);
    color: white;
    font-weight: bold;
    text-decoration: none;
    text-shadow: 0 2px 1px black;
    display: block;
    width: 4.5rem;
    height: 4.5rem;
    border-radius: 50%;
    margin: 0 5px;
    
    display: flex;
    justify-content: center;
    align-items: center;
    
    transition: all .5s ease;
}

nav ul li a:hover {
    background-color: white;
    color: rgba(0, 0, 0, 0.75);
    text-shadow: 0 2px 1px white;
}


/* ----------- main ----------- */

main {
    flex-grow: 1;
}

main > section {
    background-color: white;
    border: solid 1px lightblue;
    border-radius: 1rem;
    box-shadow: 0 2px 2px 2px rgba(0, 0, 0, 0.125);
    margin-top: 1em;
    margin-bottom: 1em;
}

main > section > h1,
main > section > h2 {
    border-bottom: solid .25em rgba(0, 109, 38, 0.35);
    margin-top: 0;
    padding-bottom: .25em;
}